In the field of aviation, it is proposed to motorize the wheels of aircraft using electric motors to allow the aircraft to move on the ground without using the engines. However, during landing, the wheels are made to rotate suddenly, which makes it necessary to protect the output member of the motor in order to prevent damage, wherein the output member can be the rotor of the motor if the motor is in direct engagement, or the output of a reduction gear interposed between the rotor and the wheel.
It has been proposed to interpose a multi-disc clutch or a dog in order to selectively separate the output member from the wheel during landing, and to connect it to the wheel only when the speed of the aircraft drops below a certain threshold.
Separation makes it possible to implement various types of test. Indeed, when the wheel is separated from the motor, it is possible to energize the motor in order to verify that it is rotating properly, using a supply current that remains below a certain threshold for a given speed of rotation. This test can be carried out on the ground, or prior to landing. Furthermore, it is possible, prior to landing, to test the resistive torque of the wheel by connecting it to the output member and making it rotate, by means of which it is possible to identify a problem in the bearings of the wheel. However, the weight of these solutions is often prohibitive. Furthermore, these devices imply breakdown risks that have to be taken into account in the design of the aircraft, and maintenance operations (lubrication, inspection, replacement of consumable elements . . . ).
It has also been proposed to use pins which extend between the output member and the element that is to be driven, for example in a double clevis type assembly, and which are calibrated to fail in shear when the torque transmitted by the pins exceeds a certain threshold (referred to as fusible pins). This connection is much more simple and requires no maintenance apart from periodic replacement of the pins. However, the motor is permanently connected to the wheel, making it impossible to test the motor independently of the wheel. Indeed, if, prior to landing, the motor is energized and an abnormal resistance is detected, it is impossible to determine whether the resistance is caused by the motor or by the wheel.